Low Complexity Subcarrier Activation Scheme for OFDM with Index Modulation

In orthogonal frequency division multiplexing with index modulation (OFDM-IM), data is mapped to subcarrier activation patterns (SAP) using look-up tables or combinatorial schemes. The complexity of these mapping schemes increases with the number of subcarriers. Therefore, they are applied to subgroups of subcarriers, but unfortunately, at the expense of reducing the amount of data loaded to an OFDM block. In this paper, low-complexity direct data to SAP mapping is proposed, the necessary analysis to determine the analytical bit error rate (BER) is presented, and the computer simulations are performed to find and compare theoretical and simulated BER results under conditions of the frequency selective Rayleigh fading channel. The proposed scheme can load more data bits to an OFDM block than conventional schemes. The results from computer simulations demonstrate the superiority of the OFDM-IM system using the proposed scheme over conventional OFDM-IM in terms of BER performance.